Air heater with safety exhaust system

ABSTRACT

An air heater for outdoor work areas including an elongated linear burner containing fire tube having a heat discharging blower mounted in alignment with and in spaced relation from the outlet end of the tube. The portion of the tube adjacent the outlet end includes upper and lower combination air inlets and gas exhausts. The unit is skid mounted for portability.

United States Patent [72] Inventor Ernest R. Muckelrath Tioga, N. Dak.[21 Appl. No. 822,849 [22] Filed Apr. 17,1969 [451 Patented Apr. 20,I971 [73] Assignee Air Heaters, Inc.

[54] AIR HEATER WITH SAFETY EXHAUST SYSTEM 5 Claims, 6 Drawing Figs.

[52] US. Cl 263/19 [51] Int. Cl F231 9/00 [50] Field of Search 263/ 1 9;126/1 10, 116

[56] References Cited UNITED STATES PATENTS 2,579,158 12/1951 Scheu263/19 2,703,706 3/1955 Bishop 263/19 2,756,040 7/1956 Golden 263/193,117,770 1/1964 Campbell 263/19 3,263,979 8/1966 Muckelrath 263/19Primary Examiner-Edward G. Favors Attorneys-Clarence A. O'Brien andHarvey B. Jacobson Pa tented 7 A ril 20, 1911 3,575,396

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I BY 22 My MR HEATER WTTH SAFETY EXHAUST SYSTEM The instant inventiongenerally relates to heater assemblies of the type utilized in heatingoutdoor work areas such as drilling rigs, construction sites and thelike. More particularly, the invention is concerned with such a heaterassembly wherein specific provision is made so as to protect the blowerand the work area itself against any possible harmful malfunctioning ofthe burner equipment.

Portable heaters of the type herein involved are normally utilized so asto maintain temperatures at outdoor worksites which allow for acontinuation of the work under reasonably comfortable conditionsregardless of prevailing cold weather conditions. In apparatus of thistype, utilizing a gas-fed burner unit, problems occasionally arise inthe equipment which could result in a highly undesirable discharge ofgas into the work area. As one example of such a situation, there mightbe a fire failure in the burner in conjunction with a failure of theappropriate control valve to cut off the gas supply. In addition to thisparticular hazard, there is also the danger of damage to the equipmentitself, and more particularly the blower should, as an example, theburner stay on because of a safety valve failure subsequent to astopping of the blower. Accordingly, it is the primary intention of theinstant invention to construct an area heater, utilizing an elongatedfire tube from which bumer-heated air is drawn and directed to aworksite by a blower, wherein substantial safety features areincorporated in a simple and highly unique manner, such being done so asto produce an extremely effective protection system in an economical andpractical manner,

In conjunction with the above object, it is a significant object of theinstant invention to provide a safe" system which, during the normaloperation thereof, provides for a complete combustion of the fuel and adependable continuous high temperature discharge.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIG. II is a side elevational view of the air heater of the instantinvention;

FIG. 2 is a top plan view thereof;

FIG. 3 is an enlarged longitudinal cross-sectional view takensubstantially on a plane passing along line 3-3 in FIG. 2;

FIG. 41 is a transverse cross-sectional view taken substantially on aplane passing along line 4-4 in FIG. 3;

FIG. 5 is a side elevational view of the air heater with an insulatingcover utilized over the fire tube and controls; and

FIG. s is a plan view of a modified form of support skid.

Referring now more specifically to the drawings, reference numeral 110is used to generally designate the portable air heater comprising theinstant invention. The heater ll0 consists basically of an elongatedhollow cylindrical fire or burner tube 12, a burner unit M mountedwithin one end of the tube 12, and a blower unit 16 positioned in spacedaligned relation to the other end of the tube 12.

The fire or burner tube 12 and blower unit 16 are normally mounted on anelongated skid llfi consisting of a pair of laterally spaced elongatedside beams 20 interconnected by transversely extending rigid pipes 22.The tube 12 will be supported in an elevated position above the skid I8by appropriate legs 24 while the blower unit 16 will be mounted on theskid 18 through an appropriate base construction 26 in a manner so as toposition the blower intake or inlet 28 at equal height and in alignmentwith the spaced outlet or discharge end 30 of the tube 12. If sodesired, an overhead support rack or frame 32 can be mounted on the skid18 for the support of blower extension tubes or ducts 34 which can beadded to the blower outlet or discharge 36, these duct sections M beingsecured by a tiedown line 37 selectively tightened by an appropriateline or chain tightener 38.

As noted previously, the burner unit 14, which can actually consist ofmultiple burners as suggested in FIG. 4, is mounted within the fire orburner tube 12 adjacent one end thereof, this one end, designated byreference numeral 40, constituting the inlet end of the tube. The inletend 40 of the tube is closed by an end wall 42 having a selectivelyopenable enlarged access panel 44 therein whereby servicing of theburner unit 14 can be easily effected. The fuel supplying and controllines 46 for the burner unit 14 extend into the first end 40 of the firetube 12 through an enlarged opening 48 through the lower portion of thetube 12 immediately forward of the end wall and closure panel 42 and 44,this opening also constituting the primary air intake for the burnerunit 14. Appropriate control valves, pressure gauges and the like,generally designated by reference numeral 50, will be located outward ofthe fire tube I2 and constitute the control means for the burner unitand gas supply lines.

Immediately inward of the outlet or discharge end 30 of the fire tube12, the tube 12 is provided with an enlarged screen protected air intake52 extending at least 180 about the tube 12 transversely about the lowerportion of the tube 12. As will be appreciated from the drawings, thisscreened air intake opening 52, which incidently also functions as a gasexhaust as shall be explained presently, extends along a substantiallength of the fire tube commencing immediately inward from the dischargeend 30.

A second air intake at the outlet or discharge end portion of the tube12 is provided in the nature of a vertical screened flue 54 projectingupwardly from the fire tube in general alignment with the inner portionof the downwardly directed opening 52, this flue 54 selectively actingin the manner of an air inlet or a gas exhaust stack. Finally, as notedpreviously, the blower unit 16 is spaced from the discharge end 30 ofthe fire or burner tube 12 so as to provide a substantial and a completeairgap or space therebetwen.

Constructed in this manner, the heater l0 inherently incorporatessignificant safety features which substantially enhance the adaptabilityof the heater for all working environments. More particularly, not onlydo the opening 52 and flue 54 provide secondary air intakes forward ofthe burner unit 14 so as to ensure a complete combustion of the fuelprior to a discharge of the heated air by the blower unit 16, but also,these openings function as exhausts should any malfunction of theapparatus occur. For example, should there be a fire failure within theburner unit 14 without a corresponding cutting off of the gas, the heavygas will merely move downwardly through the opening 52 and discharge inthe area of the heater rather than passing through the blower and airducts leading to the work area. The significant airgap between the inlet28 of the blower l6 and the discharge end 30 of the fire tube 12 alsocontributing to the gas discharging to the atmosphere prior to beingdirected to the work area.

As another example, should the blower 16 cut off without a correspondingcutting off of the burner unit and gas flow, the hot air, including theexhausted gas, will freely pass upwardly and exhaust or exit through theupwardly directed flue 54 rather than passing into the blower unit 16and causing possible damage thereto. In this particular situation, whilethe heat within the fire tube 12 can increase substantially, the firetube is specifically constructed so as to withstand the heat, and at thesame time, the significant airgap between the blower unit 16 and thefire tube 12 prevents a transmission of this heat to the blower unitwherein, in the absence of an activation of the blower unit 16,substantial damage might be done. Incidently, the air space between theblower unit 16 and the fire tube outlet end 30 also functions as anextra exhaust area for the gas and heat in the event of blower failure,as well as a means for allowing the addition of an appreciable amount offresh air during the operation of the heater which air, being taken fromclosely adjacent the fire tube 12 itself, will in fact be slightlypreheated.

Also of significance in spacing the blower unit 16 from the fire tube 12as compared to an engaged side-by-side positioning of these units, isthe elimination of any possibility of the fire tube being forced againstand possibly causing damage to the blower unit as the heater is beingmoved. In this regard, it will of course be appreciated that the use ofthe heater at remote outdoor worksites will require a subjecting of theheater to relatively rough handling, this in turn requiring a ruggedtrouble-free construction.

Referring specifically to FlG. 5, it should be recognized that theheater assembly of the instant invention can provide for an enclosing ofthe fire tube 12 within an insulated protective housing 56, this housing56 also enclosing the control apparatus 50. As will be appreciated fromFIG. 5, the fire tube discharge end 30 as well as the flue 54 will opendirectly through the housing walls 56 with the end of the housing beinggenerally coextensive with the discharge end 30 of the fire tube 12 soas to retain the complete airspace or gap between the blower unit 16 andfire tube 12. In addition, if deemed desirable so as to accommodate theair intake or gas exhausting action of the fire tube opening 52, theadjacent end wall of the housing 56 can be entirely open below the firetube discharge end 30, or alternatively suitable grilled openings can beprovided through the lateral sidewalls of the housing 56 adjacent thisend of the fire tube 12.

Referring now to FIG. 6, an enlarged skid 58 has been illustratedtherein, this skid 58 incorporating an additional laterally joinedsection 60 for transporting additional air duct section 62 either inconjunction with or in place of the overhead rack 32 provided on theskid 18.

From the foregoing, it will be appreciated that a unique heater assemblyhas been defined. This heater assembly includes a fire tube comprising asingle straight length of constant diameter hollow tubing, so as toachieve maximum heat flow from the burner unit, and a safety exhaustsystem which protects both the blower unit and the actual work areashould any malfunction of the equipment occur. This exhaust meansincludes, in addition to an enlarged downwardly directed screened orgrill-covered opening for heavy gas and an upwardly directed screened orgrill-covered flue for lighter burned or exhaust gas, a specificcomplete airgap between the open discharge end of the fire tube and theblower unit itself.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention.

lclaim:

l. A heater assembly comprising an elongated fire tube, said fire tubeincluding first and second ends, burner means mounted within said firetube adjacent the first end, the second end of said fire tube being openand constituting the discharge end, blower means longitudinally alignedwith and spaced from said discharge end for the drawing of burner heatedair therefrom and the discharge of the air to an outwardly located area,and combination combustion supporting air inlet and gas exhaust meanswithin said fire tube adjacent the discharge end thereof, saidcombination means being orientated relative to the burner means wherebyair introduced therethrough will insure a substantially completecombustion of the fuel prior to discharge of the heated air, saidcombination air inlet and gas exhaust means including an upwardlydirected flue through the top of said fire tube and a downwardlydirected opening transversely across the lower portion of said firetube.

2. The heater assembly of claim 1 wherein said fire tube includes aprimary air inlet therethrough adjacent said burner means, said firetube being of a constant cross section along the full length thereof.

3. The heater assembly of claim 1 wherein the downwardly directedopening transversely across the fire tube extends about the tube for atleast approximately 4. A portable area heating heater assemblycomprising an elongated fire tube including first and second ends,burner means mounted within said fire tube adjacent the first endthereof, primary arr inlet means in said tube adjacent said burnermeans, the second end of said fire tube constituting the discharge end,blower means positioned adjacent the discharge end of said fire tube forthe drawing of heated air therefrom, and first and second combinationsecondary combustion air inlets and gas exhaust openings through saidfire tube immediately adjacent the discharge end thereof and in directcommunication with the atmosphere, the first and second combinationopenings comprising an upwardly directed opening through the top of saidfire tube and a downwardly directed opening through the bottom of saidfire tube in general alignment with each other, said openings beingorientated relative to the burner means whereby air introducedtherethrough will insure a substantially complete combustion of the fuelprior to discharge of the heated air, the upwardly directed openingcomprising a screened flue, and the downwardly directed opening beingelongated transversely across the lower portion of the fire tube andscreen protected.

5. A portable area heating heater assembly comprising an elongated firetube including first and second ends, burner means mounted within saidfire tube adjacent the first end thereof, primary air inlet means insaid tube adjacent said burner means, the second end of said fire tubeconstituting the discharge end, blower means positioned adjacent thedischarge end of said fire tube for the drawing of heated air therefrom,and first and second combination secondary combustion air inlets and gasexhaust openings through said fire tube immediately adjacent thedischarge end thereof and in direct communication with the atmosphere,the first and second combination openings comprising an upwardlydirected opening through the top of said fire tube and a downwardlydirected opening through the bottom of said fire tube in generalalignment with each other, said openings being orientated relative tothe burner means whereby air introduced therethrough will insure asubstantially complete combustion of the fuel prior to discharge of theheated air, said blower being longitudinally spaced from the dischargeend of the fire tube so as to define a complete airgap therebetween.

1. A heater assembly comprising an elongated fire tube, said fire tubeincluding first and second ends, burner means mounted within said firetube adjacent the first end, the second end of said fire tube being openand constituting the discharge end, blower means longitudinally alignedwith and spaced from said discharge end for the drawing of burner heatedair therefrom and the discharge of the air to an outwardly located area,and combination combustion supporting air inlet and gas exhaust meanswithin said fire tube adjacent the discharge end thereof, saidcombination means being orientated relative to the burner means wherebyair introduced therethrough will insure a substantially completecombustion of the fuel prior to discharge of the heated air, saidcombination air inlet and gas exhaust means including an upwardlydirected flue through the top of said fire tube and a downwardlydirected opening transversely across the lower portion of said firetube.
 2. The heater assembly of claim 1 wherein said fire tube includesa primary air inlet therethrough adjacent said burner means, said firetube being of a constant cross section along the full length thereof. 3.The heater assembly of claim 1 wherein the downwardly directed openingtransversely across the fire tube extends about the tube for at leastapproximately 180*.
 4. A portable area heating heater assemblycomprising an elongated fire tube including first and second ends,burner means mounted within said fire tube adjacent the first endthereof, primary air inlet means in said tube adjacent said burnermeans, the second end of said fire tube constituting the discharge end,blower means positioned adjacent the discharge end of said fire tube forthe drawing of heated air therefrom, and first and second combinationsecondary combustion air inlets and gas exhaust openings through saidfire tube immediately adjacent the discharge end thereof and in directcommunication with the atmosphere, the first and second combinationopenings comprising an upwardly directed opening through the top of saidfire tube and a downwardly directed opening through the bottom of saidfire tube in general alignment with each other, said openings beingorientated relative to the burner means whereby air introducedtherethrough will insure a substantially complete combustion of the fuelprior to discharge of the heated air, the upwardly directed openingcomprising a screened flue, and the downwardly directed opening beingelongated transversely across the lower portion of the fire tube andscreen protected.
 5. A portable area heating heater assembly comprisingan elongated fire tube including first and second ends, burner meansmounted within said fire tube adjacent the first end thereof, primaryair inlet means in said tube adjacent said burner means, the second endof said fire tube constituting the discharge end, blower meanspositioned adjacent the discharge end of said fire tube for the drawingof heated air therefrom, and first and second combination secondarycombustion air inlets and gas exhaust openings through said fire tubeimmediately adjacent the discharge end thereof and in directcommunication with the atmosphere, the first and second combinationopenings comprising an upwardly directed opening through the top of saidfire tube and a downwardly directed opening through the bottom of saidfire tube in general alignment with each other, said openings beingorientated relative to the burner means whereby air introducedtherethrough will insure a substantially complete combustion of the fuelprior to discharge of the heated air, said blower being longitudinallyspaced from the discharge end of the fire tube so as to define acomplete airgap therebetween.